The present invention relates, generally, to the field of surgical clips and, in particular, to the field of surgical clips including a shape memory alloy (SMA).
Several methods are known in the art for joining portions of hollow organs, such as those of the gastrointestinal tract. These include threads for manual suturing, staplers for mechanical suturing, and compression rings and clips.
While manual suturing is universally known and relatively inexpensive, the degree of success depends considerably on the skill of the surgeon. Another disadvantage is that post-operative complications are common. Further, suturing an organ results in lack of smoothness of the tissue therein, which hampers peristalsis in the sutured area. Finally, suturing is both labor and time consuming.
Staplers for mechanical suturing ensure a reliable joining of tissue and enable the time needed for surgery to be reduced, compared with manual suturing. However, due to the facts that such staples are not reusable and that a great many types and sizes are required, the price of staples is high. Also, after healing, metal staples remain in place along the perimeter of the suture, which reduces elasticity of the junction and adversely affects peristalsis.
Junctions using compression devices such as rings and clips ensure high quality seal and post-operative functioning of the organs. Two types of compression devices are known, namely, rings made of resorption plastics and clips made of shape memory alloys. Plastic rings are cumbersome and expensive. Also, the compression force is applied only momentarily at the junction and is reduced as the tissue is crushed. Clips made of shape memory alloys enable portions of tissue to be pressed together with increasing pressure and to provide constant pressure at body temperature, due to the inherent properties of the alloys.
Advantages of clips made of shape memory alloy materials include simplicity of design, low cost of manufacture, and smallness in size. Also, they possess universal qualities and they ensure their self-evacuation from the gastrointestinal tract.
It is known in the art to provide a surgical fastening clip which applies a clamping force to a site, such as a blood vessel, thereby reducing its cross-sectional area. It is also known to provide a surgical fastening clip formed of a shape memory alloy which deforms to a closed configuration when heated, such that the clamping force applied thereby is increased as it is heated. For example, U.S. Pat. No. 5,171,252 discloses a surgical fastening clip formed of a shape memory alloy, the device including separate legs which close tightly around a site. Such a device is limited in its uses, such as for clamping blood vessels, and is not suitable for joining portions of the gastrointestinal tract.
EP 0,326,757 discloses a device for providing anastomosis to a portion of a digestive tract, including a plurality of U-shaped retaining clips disposed around a soluble support tube. The tube is positioned inside portions of the digestive tract to be joined, and includes an outer groove around which are disposed the U-shaped retaining clips. The retaining clips are made of a shape memory alloy such that the open ends thereof close at a predetermined temperature, thus joining ends of the digestive tract. Once the ends of the digestive tract have been joined, the tube is dissolved. Such a device is disadvantageous in that a plurality of clips are required to be properly positioned simultaneously. Also, there is no assurance that the resulting junction will be smooth, due to the plurality of sites of the digestive tract joined by the plurality of clips.
SU 1,186,199 discloses a shape memory alloy clip consisting of two parallel coils which is used for joining portions of a hollow organ, such as an organ of the gastrointestinal tract. The portions of the organ to be joined are aligned and each of the coils is introduced through a puncture formed in the wall of one of the portions. The coils are positioned such that, when heated, they compress the aligned walls therebetween, thus maintaining the portions of the walls held within the loops of the coils adjacent each other. Thereafter, incisions are made through the portions of the walls held within the loops of the coils, such that a passageway is created between the two organ portions. The punctures in the organ walls must then be surgically sewn closed with interrupted surgical sutures.
A major disadvantage of this sort of shape memory alloy clips is that they permit compression of only approximately 80-85% of the junction perimeter, thus requiring additional manual sutures which reduce the seal of the junction during the healing period and its elasticity in the post-operative period. Furthermore, this additional suturing is problematic in as much as it has to be carried out across a join which includes a portion of the clip, thereby rendering difficult sealing and anastomosis of the organ portions.
The present invention seeks to provide an improved surgical clip system including a shape memory alloy, and a method of joining two portions of a hollow organ, which overcome disadvantages of prior art.
There is thus provided, in accordance with a preferred embodiment of the present invention, a surgical clip system which includes a surgical clip having a first clip portion including a first length of material having a closed geometrical shape having a first surface, the shape having a central axis therethrough and having a central opening therein; a pair of support portions associated with the first clip portion; a second clip portion including a second length of material having a closed geometrical shape having a second surface of substantially the same configuration and size as that of the first clip portion, the shape having a central axis therethrough; and a pair of fastening elements formed of a shape memory alloy, each of the fastening elements including a first end and a second end, each of the first ends being attached to the second clip portion; wherein, when at a first temperature or higher, the shape memory alloy is in an elastic state, such that the pair of fastening elements are maintained in a position such that they abut the support portions, and wherein, when at a second temperature or lower, below the first temperature, the shape memory alloy is in a plastic state, thereby enabling the second ends of the pair of fastening elements to be moved away from the second length of material and to be passed between the support portions such that, upon heating of the clip to at least the first temperature, the pair of fastening elements returns to the position such that they abut the support portions, thereby pressing against the pair of support portions, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material.
Additionally in accordance with a preferred embodiment of the present invention, the first clip portion, the support portions, and the second clip portion are fabricated from biocompatible material.
Further in accordance with a preferred embodiment of the present invention, each of the pair of support portions includes a pair of guide elements between which one of the fastening elements is positioned when in the elastic state and when the first and second lengths of material are pressed towards each other.
Yet further in accordance with a preferred embodiment of the present invention, the guide elements are fabricated from biocompatible material.
Still further in accordance with a preferred embodiment of the present invention, upon heating of the clip to at least the first temperature, the pair of fastening elements press against the pair of support portions, thereby pressing the first and second lengths of material towards each other such that they are maintained a distance apart of approximately 0.1-1.5 mm.
In accordance with another embodiment of the present invention, upon heating of the clip to at least the first temperature, the pair of fastening elements press against the pair of support portions, thereby pressing the first and second lengths of material against each other such that the first and second surfaces substantially abut each other.
In accordance with the present invention, the system further includes spacer means for facilitating movement of the second ends of the fastening elements away from the second length of material. The spacer means includes means insertable through the second length of material of the second clip portion. The insertable means includes means for guiding movement of the fastening elements away from the second length of material. The spacer means is fabricated from biocompatible material.
In accordance with a second embodiment of the present invention, there is provided a surgical clip system which includes a surgical clip having: a first clip portion including a first length of material having a closed geometrical shape having a first surface, the shape having a central axis therethrough and having a central opening therein; a pair of support portions associated with the first clip portion; a second clip portion including a second length of material having a closed geometrical shape having a second surface of substantially the same configuration and size as that of the first clip portion, the shape having a central axis therethrough; and a pair of fastening elements formed of a superelastic material, each of the fastening elements including a first end and a second end, each of the first ends being attached to the second clip portion; wherein, in the absence of an outside force, the pair of fastening elements are maintained in a position such that they abut the support portions, and wherein, by the application of an outside force, the second ends of the pair of fastening elements are movable away from the second length of material such that they may be passed between the support portions such that, upon removal of the outside force, the pair of fastening elements returns to the position such that they abut the support portions, thereby pressing thereagainst, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material.
In accordance with a preferred embodiment of the present invention, there is provided a method for anastomosing an organ of a gastrointestinal tract, the method comprising the following steps: (a) providing a surgical clip system which includes a surgical clip having: a first clip portion including a first length of material having a closed geometrical shape having a first surface, the shape having a central axis therethrough and having a central opening therein; a pair of support portions associated with the first clip portion; a second clip portion including a second length of material having a closed geometrical shape having a second surface of substantially the same configuration and size as that of the first clip portion, the shape having a central axis therethrough; and a pair of fastening elements formed of a shape memory alloy, each of the fastening elements including a first end and a second end, each of the first ends being attached to the second clip portion; wherein, when at a first temperature or higher, the shape memory alloy is in an elastic state, such that the pair of fastening elements are maintained in a position such that they abut the support portions, and wherein, when at a second temperature or lower, below the first temperature, the shape memory alloy is in a plastic state, thereby enabling the second ends of the pair of fastening elements to be moved away from the second length of material and to be passed between the support portions such that, upon heating of the clip to at least the first temperature, the pair of fastening elements returns to the position such that they abut the support portions, thereby pressing thereagainst, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material; (b) cooling at least the fastening elements of the clip to a temperature below its lower phase transition temperature; (c) moving the second ends of the fastening elements away from the second length of material; (d) preparing open ends of first and second organ portions to be joined, such that a cross-sectional area of each organ portion is narrowed relative to the remainder of thereof; (e) inserting the first clip portion into the first organ portion, such that the first length of material abuts the inside surface of the tissue thereof, adjacent the narrowed area thereof; (f) inserting the second clip portion into the second organ portion, such that the second length of material abuts the inside surface of the tissue thereof, adjacent the narrowed area thereof and such that the fastening elements protrude out of the open end of the second organ portion; (g) drawing together the open ends of the first and second organ portions wherein anastomosis is desired such that they face each other, and bringing the open ends closer together such that the fastening elements protruding out of the open end of the second organ portion pass into the open end of the first organ portion, through the first length of material, and through the pair of support portions; (h) maintaining the relative positions of the first and second portions of the gastrointestinal tract and the first and second clip portions in relation thereto, while raising the temperature of at least the fastening elements to a temperature above its upper phase transition temperature, such that the elasticity thereof causes the fastening elements to return to a position such that the fastening elements press against the pair of support portions, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material.
Additionally in accordance with the preferred embodiment of the present invention, in the step (h), the temperature of at least the fastening elements is raised to a temperature above its upper phase transition temperature by the artificial application of heat.
Further in accordance with the preferred embodiment of the present invention, the surgical clip system further includes spacer means for facilitating movement of the second ends of the fastening elements away from the second length of material; and, between steps (e) and (f), the method includes the additional step (e1) of: inserting the spacer means into the second organ portion. Between steps (f) and (g), the method includes the additional step (f1) of inserting the spacer means through the second length of material of the second clip portion, the fastening elements guided away from the second length of material. The spacer means is fabricated from biocompatible material.
In accordance with a second embodiment of the present invention, there is provided a method for anastomosing an organ of a gastrointestinal tract, the method comprising the following steps: (a) providing a surgical clip system which includes a surgical clip having: a first clip portion including a first length of material having a closed geometrical shape having a first surface, the shape having a central axis therethrough and having a central opening therein; a pair of support portions associated with the first clip portion; a second clip portion including a second length of material having a closed geometrical shape having a second surface of substantially the same configuration and size as that of the first clip portion, the shape having a central axis therethrough; and a pair of fastening elements formed of a thermoresilient material, each of the fastening elements including a first end and a second end, each of the first ends being attached to the second clip portion; wherein, in the absence of an outside force, the pair of fastening elements are maintained in a position such that they abut the support portions and wherein, by the application of an outside force, the second ends of the pair of fastening elements are moved away from the second length of material such that they are able to be passed between the support portions such that, upon removal of the outside force, the pair of fastening elements returns to the position such that they abut the support portions, thereby pressing, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material; (b) moving the second ends of the fastening elements away from the second length of material; (c) preparing open ends of first and second organ portions to be joined, such that a cross-sectional area of each organ portion is narrowed relative to the remainder of thereof; (d) inserting the first clip portion into the first organ portion, such that the first length of material abuts the inside surface of the tissue thereof, adjacent the narrowed area thereof; (e) inserting the second clip portion into the second organ portion, such that the second length of material abuts the inside surface of the tissue thereof, adjacent the narrowed area thereof and such that the fastening elements protrude out of the open end of the second organ portion; (f) drawing together the open ends of the first and second organ portions wherein anastomosis is desired such that they face each other, and bringing the open ends closer together such that the fastening elements protruding out of the open end of the second organ portion pass into the open end of the first organ portion, through the first length of material, and through the pair of support portions; (g) maintaining the relative positions of the first and second portions of the gastrointestinal tract and the first and second clip portions in relation thereto, while removing the outside force, thereby allowing the fastening elements to return to a position such that the fastening elements press against the pair of support portions, thereby pressing the first and second lengths of material towards each other, thereby to apply a compressive force to tissue located between the first and second lengths of material.